The present invention relates to an improved method of, and apparatus for, cooling and supporting a strand in a plate mold of a continuous casting installation, especially for casting steel strands, during a change in casting parameters, in particular during displacement of a mold wall arranged between wide side walls of the mold for changing the strand cross-section or format.
It is known in strand casting installations, particularly in steel strand casting installations, to use plate molds having a hollow mold compartment of adjustable width. In such plate molds the narrow side walls are arranged between the wide side walls and are displaceable transversely with respect to the strand travel or running direction by means of suitable displacement devices, such as spindles and so forth.
Recently, it has furthermore become known to change the strand format also during a running casting operation. Here, the displacement devices are operated by remote control.
In a state-of-the-art format adjusting method as known, for example from U.S. Pat. No. 4,356,862, granted Nov. 2, 1982 and as used in steel strand casting installations, brief adjusting times and short transitional pieces in the cast strand are achieved by providing two displacement devices disposed in tandem at one narrow side of the mold with respect to the strand travel or running direction. The displacement devices are operated in such a manner that during the pivoting displacement of the mold wall there is altered the mutual ratio of the rates of displacement of the two displacement devices. With this method the formation of a gap intermediate the mold wall and the solidified shell or skin of the strand is reduced. By using this method the deformation of the solidified strand shell also can be maintained within narrow limits if there is not selected a too high rate of displacement or pivoting rate of the mold wall, respectively. Although small air gaps are partially compensated by local bulging at the central range or region of the narrow side of the mold, the cooling capacity decreases at the edge regions, whereby the danger of metal break-outs is increased and the operational reliability of the equipment is reduced. To prevent such metal break-outs, according to this adjusting method there can be hardly avoided relatively long transitional pieces between two different formats of the cast strand of, for example, 2.5 meters for a change of 50 mm in width.